Endocarditis and a pacemaker or defibrillator:
how to recognize a device infection

Article written and reviewed by Dr Luca Moretti

A pacemaker, implantable defibrillator or cardiac resynchronization device can become infected in the area beneath the skin where the generator is located, along the leads that reach the heart, or at the level of the endocardium and valves. The most important local signs are redness, pain, swelling, drainage, wound opening or exposure of the device. Fever, chills and malaise may instead indicate a deeper or systemic infection.
The presence of fever in a person with a pacemaker or defibrillator does not automatically mean endocarditis, but persistent fever or fever without a clear cause warrants medical assessment, especially if it is accompanied by signs at the implant site or positive blood cultures.

Prompt assessment is advisable if any of the following occur:

• redness, warmth, pain or swelling over the generator;
• drainage, pus, persistent crusting or wound opening;
• thinning of the skin with the device or lead becoming visible;
• fever, chills or sweating without an obvious cause;
• marked fatigue or unexplained deterioration in general condition;
• shortness of breath, chest pain or new respiratory symptoms when infection is suspected.

Cardiac device-related endocarditis is a different condition from simple superficial redness of the scar. This guide explains which signs should raise suspicion of a pacemaker or defibrillator infection, which tests are used and why, when infection is confirmed, treatment often also requires removal of the system.

Where the infection may be located: pocket, leads and heart

The pacemaker or defibrillator generator is normally placed in a subcutaneous pocket, usually in the upper chest. Infection may remain confined to this site or extend along the leads that pass through a vein and reach the cardiac chambers. When the intracardiac leads, endocardium or a valve are involved, the condition becomes a systemic device-related infection and endocarditis.
Infection may appear after implantation, after generator replacement or system revision, but it can also develop much later. In the latter case, the device may be colonized by microorganisms that have reached it through the bloodstream from another infection in the body.

Simple superficial inflammation of the scar in the early period after the procedure does not necessarily mean device infection. The distinction, however, should not be made independently by observing the wound at home. A true pocket infection can begin with apparently mild signs and then progress.
If the generator or part of a lead becomes exposed through the skin, the system is considered contaminated or infected even in the absence of obvious fever. Covering the area, applying disinfectants or starting antibiotics without specialist assessment does not eradicate infection of implanted material.

Local symptoms to monitor over the pacemaker or defibrillator site

The most recognizable signs are those involving the device pocket: redness that increases rather than subsides, pain or tenderness, warmth, swelling, skin tension and drainage. A wound that reopens, a sinus tract that continues to drain material or progressive deformation of the pocket requires particular attention.
Slow erosion of the skin is also important. The device may become more prominent, adhere to the skin and eventually protrude through it. This process may cause little pain and may not be accompanied by fever, but it is not benign.

In the days immediately after implantation, pain, bruising and some swelling may occur. What should increase suspicion above all is worsening instead of improvement, the appearance of drainage, reopening of the wound or inflammation that persists.
If there is any doubt, it is preferable to contact the center that follows the device. Manipulating the pocket, squeezing drainage or applying antibiotic creams can alter the local appearance without treating a possible deep infection.

When the infection is deep: fever and symptoms may occur without pocket signs

Lead infection or device-related endocarditis may present like a typical systemic infection: fever, chills, sweating, fatigue, loss of appetite and malaise. The pocket may appear completely normal, so the absence of chest redness does not exclude the problem.
Suspicion becomes particularly important when Staphylococcus aureus is identified in the bloodstream, because this microorganism has a marked ability to adhere to intravascular material and infect the system. Persistent or recurrent bacteremia without another clear focus also requires assessment of the device.

Because the leads pass through the right-sided chambers of the heart, infected fragments can reach the lungs. Some patients may therefore develop shortness of breath, pleuritic chest pain, cough or pulmonary imaging findings compatible with septic emboli. These symptoms are nonspecific and do not allow diagnosis at home, but they are among the possible presentations.
If severe breathing difficulty, syncope, altered level of consciousness or rapid deterioration in general condition occurs, urgent assessment through the emergency medical system is required.

How device infection is diagnosed

Diagnosis combines examination of the pocket, blood cultures and imaging techniques. If the patient is stable, blood cultures are obtained before antibiotics are started, because identifying the microorganism helps distinguish contamination from true bacteremia and allows the most appropriate treatment to be selected.
When intracardiac involvement is suspected, both transthoracic echocardiography and transesophageal echocardiography are used. Transesophageal echocardiography provides better visualization of the leads and valves, but even a negative study does not always exclude infection.

If suspicion remains high, guidelines recommend repeating echocardiography after several days and integrating imaging when necessary. 18F-FDG PET/CT can be particularly useful in possible or uncertain cases, especially when there are no obvious pocket signs; after very recent implantation, however, postoperative inflammation can complicate interpretation.
Chest radiography or CT may also be used to look for pulmonary complications. A mobile mass on a lead does not automatically mean infection, because noninfectious fibrinous deposits can also occur: imaging findings must therefore be interpreted together with symptoms, blood cultures and other clinical data.

Why the entire device often has to be removed and antibiotics alone are not enough

When a true infection of the pocket or leads, or device-related endocarditis, is confirmed, the standard treatment is complete removal of the system together with antimicrobial therapy. The biofilm that forms on the surface of the generator and leads makes it difficult to eradicate the infection while contaminated material remains in place.
Removal normally includes both generator and leads and should be performed without unnecessary delay in a center experienced in transvenous lead extraction and capable of managing complications. Replacing only the generator while leaving infected leads in place does not constitute complete eradication of the infectious source.

After extraction, antibiotics are administered for a duration that depends on the site of infection, the microorganism, the presence of bacteremia or endocarditis and any complications. The need to implant a new pacemaker or defibrillator is reassessed from the beginning: some patients no longer have an indication, whereas others remain device-dependent.
When a new implant is required, removed material is not reused and the new system is generally placed at a different site after the infection has been controlled. The exact timing depends on the clinical picture and clearance of blood cultures.

Finally, the mere presence of a pacemaker or defibrillator does not mean that antibiotics are needed before dental procedures. Dental prophylaxis depends on other high-risk cardiac conditions, such as previous endocarditis or certain prosthetic valves. For people who only have a CIED, guidelines do not recommend antibiotic prophylaxis specifically to prevent device infection during dental treatment.

Frequently asked questions about pacemakers, defibrillators and infection

Does redness over the pacemaker always mean infection?
No. After implantation, bruising, pain and local inflammation may occur. However, redness that increases, drainage, wound opening, increasing pain or exposure of the device requires assessment.

Can device-related endocarditis occur with a normal pocket?
Yes. The infection may mainly involve the leads or bloodstream and present with fever and other systemic symptoms without obvious skin signs.

If echocardiography does not show vegetations, is infection excluded?
No. Vegetations may not be visible and some portions of the leads are difficult to assess. If suspicion remains high, repeat echocardiography and other tests, such as PET/CT, may be necessary.

Are antibiotics enough?
As a rule, no in confirmed infections of the system. Standard treatment combines antibiotics with complete removal of the infected device.

Is a new device always implanted immediately after extraction?
No. The indication is reassessed first and, if the device remains necessary, reimplantation is scheduled once the infection is under control according to the individual patient’s condition.